Regulation of the lens, the role of the lens

Lens accommodation is adjusted by a negative feedback mechanism that automatically adjusts the focus of the lens to achieve the highest visual acuity. When the eye fixes on a distant target and then suddenly fixes on a near target, the lens adjusts to its highest visual acuity within 1 second. The exact mechanism that makes the eye focus so quickly and so accurately is unclear.

Some of the features of this mechanism are already known: First, when the eye suddenly changes the distance of the fixation point, the lens must change its power in the appropriate direction to reach a new state of focus. In other words, the lens generally does not explore back and forth on both sides of the focal point in order to find the focal point.

Second, there are different types of cues that can help the lens change its power in the appropriate direction, including the following: (1) chromatic aberration appears to be important, i.e., red light rays are focused slightly behind the retina than blue rays. It seems that the eye is able to distinguish which of the two types of light is better focused, and this cue transmits information to the regulatory mechanism to increase or weaken the power of the lens.

2) When the eyeball fixes on a nearby object, the two eyes converge inward with each other. The neural mechanism of the radiation causes an excitatory signal that increases the power of the lens of the eye. (3) Since the fovea is a concave area, the sharpness of focusing in the deep part of the depression is different from the sharpness of focusing at the edges.

It is thought that this also provides clues as to how the lens needs to change its power. (4) It has been found that the degree of adjustment of the lens has been fluctuating slightly at a frequency of about 1 2 2 times per second. "I think that when the power of the lens fluctuates in the right direction, the visual image becomes clearer and less clear in the wrong direction.

This gives a quick clue as to which direction the power of the lens needs to be shifted in order to focus better.

The crystals are about 9 mm in diameter, biconvex, and slightly flatter in front than in the back. Its anterior position is about the anterior apex of the cornea. When there is no adjustment, the radius of curvature of the front and back.

each is + and (Gullstrand data), and the thickness is . The refraction is changed by contraction or relaxation of the ciliary muscle, so that the focus of the eyeball can accurately fall on the retina when looking far or near. Above.

The lens is one of the most important refractive interstitium in the eyeball. The lens is like a lens in a camera, which has a refractive effect on light, and can also filter out some ultraviolet rays and protect the retina, but its most important role is to change the refraction through the contraction or relaxation of the ciliary muscle, so that the focus of the eyeball can accurately fall on the retina when looking far or near.

The crystal refractive power is a part of the total refractive power of the eye and plays a role in balancing the refractive power of the eye. In addition, the crystal also provides a focusing effect on different distances, which is called adjustment.

Crystals undergo a series of aging changes with age, which affects their elasticity and transparency. The crystalline part is encased in an elastic capsule. The suspensory ligament of the crystal extends from the periphery of the capsule to the ciliary body, supports the position of the crystal, and produces a change in the tension of the small band by the action of the ciliary muscle, which changes the curvature of the crystal surface.

Summary. Answer: The regulating force of the crystal refers to the deformation ability of the crystal under the action of external force.

It is an important property of crystal structure and can reflect the elasticity and hardness of the crystal. The regulating force of the crystal depends on the structure, composition, and structural parameters of the crystal, as well as the temperature, humidity, and magnitude of the external forces of the crystal. In order to improve the regulating force of the crystal, it is necessary to change the structure and composition of the crystal first, so as to make the structural parameters of the crystal more reasonable, so as to increase the elasticity and hardness of the crystal.

Secondly, the temperature, humidity and external force of the crystal should be controlled to reduce the deformation of the crystal. Finally, some special technologies, such as heat treatment, surface treatment, etc., should be adopted to improve the regulating power of the crystal.

Answer: The regulating force of the crystal refers to the deformation ability of the crystal under the action of external force. It is an important property of the coarse structure of crystal junctions, which can reflect the elasticity and hardness of crystals.

The regulating force of the crystal depends on the structure, composition, and structural parameters of the crystal, as well as the temperature, humidity, and magnitude of the external forces of the crystal. In order to improve the regulating power of the crystal reed stool, it is necessary to change the structure and composition of the crystal first, so as to make the structural parameters of the crystal more reasonable, so as to increase the elasticity and hardness of the crystal. Secondly, the temperature, humidity and external force of the crystal should be controlled to reduce the deformation of the crystal.

Finally, some special technologies, such as heat treatment, surface treatment, etc., should be adopted to improve the regulating power of the crystal.

I'm still a little confused, can you be more detailed?

The regulatory power of a crystal refers to the ability of a crystal to adjust its structure to maintain its function when the external environment changes. The regulatory force of a crystal can be measured by the structure, physical properties, and chemical properties of the crystal. The structure of a crystal refers to the crystal structure of a crystal, which is a three-dimensional space configuration composed of crystal atoms or molecules, which determines the physical and chemical properties of the crystal.

The physical properties of a crystal refer to the physical properties of the crystal, such as the thermal stability, thermal conductivity, electrical conductivity, magnetic permeability, etc., which determine the regulating force of the crystal. The chemical properties of the crystal refer to the chemical properties of the crystal, such as the solubility of the crystal, corrosion resistance, oxidation resistance, etc., which also determine the regulatory power of the crystal. The regulatory power of the crystal can be improved by changing the structure, physical properties, and chemical properties of the crystal.

For example, the physical and chemical properties of the crystal can be changed by changing the crystal structure of the crystal, so as to improve the regulatory power of the crystal. In addition, the physical and chemical properties of the crystal can also be changed by changing the external environmental conditions such as temperature, pressure and humidity of the crystal, so as to improve the regulating power of the crystal. In conclusion, the regulatory power of a crystal refers to the ability of a crystal to adjust its structure in order to maintain its function when the external environment changes.

The regulatory power of the crystal can be improved by changing the structure, physical and chemical properties of the crystal, and can also be improved by changing the external environmental conditions.

Playing table tennis is the best way to exercise!

The cylindrical crystal has a problem with the ability to adjust, which is innate, unable to adjust the function of the eye, which allows us to see things in the dark.

It is the vitreous and lens, and the cornea is on the surface of the eye, not in the eye.

The lens is an important part of the refractive system of the eyeball, and it is also the only refractive interstitium with the ability to adjust, and its ability to adjust gradually decreases with age, forming the phenomenon of presbyopia.

Relax the lens.

The most common way to do this is to do eye exercises twice a day, and remember to look at each other at intervals after watching TV or using the computer for a long time. Also, remember to wash your face and eyes before going to bed with your eyes closed. Hope it helps.

Use the lower part of the palm of the hand, a lot of flesh, and tap the eyebrows, and the lower part of the palm is a little nested under the eyebrows.

If they are sore at first, tap them gently as hard as you can. Shake it up and down to relax the whole eye well. And if there is a person with heart disease, the place will be particularly sour, and it will be sore at the slightest touch.

It's okay, take your time, it'll get looser and looser every day. Long-term persistence, nothing to beat, eyes can not be old.

The ciliary body is the thickened part of the membrane in the wall of the eyeball, and there are many protruding and radially arranged folds on the inner surface. Therefore, I personally believe that the ciliary body relaxes, the strength of the traction lens decreases, and the curvature of the lens increases under the action of elasticity, on the contrary, the ciliary body contracts, the strength of the traction lens increases, and the lens is flattened under the action of traction, showing a decrease in the curvature of the lens.

The "Physics" under the eighth grade of the People's Education Edition is introduced like this: the ciliary body shrinks, and the lens thickness increases. That is, the ciliary body shrinks and the lens curvature increases; The ciliary body is dilated, and the curvature of the lens decreases.

How should this be explained?